Research Subjects

Flux measurement --> more
Remote sensing Application -->
Glacier and snow melting -->
Runoff analysis -->

Snow water resources --> more
Nutrient and fertilization -->
Economic evaluation -->
Health risk assessment -->

Habitat estimation --> more
Genetic diversity -->

Flood damage cost projection --> more
Landslide projection -->

Hydrological Processes

Flux measurement
We are measuring latent and sensible heat fluxes to know energy balance on the surface. This measurement can be used for understanding of thermal environment and energy cycle. The results are applied to urban planning and reduction of water loss by evapotranspiration.

Measurement system of fluxes on a tower in Thailand
(Komori et al., Journal of Agricultural Meteorology, 60(5), pp.529-532, 2005)


Remote sensing Application
Remote sensing provides wide information for water cycle. Albedo on glacier and evapotranspiration on vegetation areas are estimated using multi-spectral sensors.

mm/month
Evapotranspiration from April to November estimated in the Natori River Basin using NDVI
L: direct NDVI method, R: Single Layer model
(Watanabe et al., IAHS Red Book, 289, pp.392-400, 2004.)


Glacier and snow melting
Glacier and snow are the most sensitive for global warming. The disappearance of glacier affects not only water resources but more global warming. We are measuring glacier and snow and developing models estimating the change.

Snowboarding with high accurate GPS to measure snow surface elevation in Zao Mt.


Runoff analysis
Runoff simulation can tell us about water movement in a basin and and risk of drought and flood. We must consider distribution of precipitation, evapotranspiration, surface and subsurface flow. Also storage of snow and paddy field is important. Runoff model integrates all hydrological processes.

Distribution of water depth in the Natori River Basin simulated by a hydrological model

Water Resources Analysis

Snow water resources
Snow is called a white dam in Japan. The storage water is huge and used for rice planting in spring season. How large does snow storage amount correspond to paddy field? How much will we miss out on paddy field after global warming? We seek those answers.

Snow depth change simulation in Japan
(Kazama et al., Hydrological Processes, 22(13), pp.2315-2324, 2008.)


Nutrient and fertilization
Flood inundation in the Mekong River produces many benefits such as fishery production, groundwater resources and fertile grounds. The fertilizer effect of the inundation produces sustainable crop production if farmers plant suitable number of crops. To know this, we measure the amount of nutrient in inundation areas.

Water sampling and analysis in Cambodia
(Amano et al., Journal of Water and Environment Technology, 10(2), pp.165-175, 2012.)


Economic evaluation
Evaluation of cost and benefit of water is helpful for comparing with other items. Especially the future projection can contribute to ground design and developing planning. This areal study needs economics and mathematics for numerical modeling.

Relationship between benefit products and inundation area in time series in the lower Mekong. Zoom in this to see mode details.
(Kazama et al., Hydrological Processes, 23(4), pp.623-632, 2009. )


Health risk assessment
Inundation water brings not only nutrient but also bacteria and virus. These are one of the most serious risks in flood. So that, it is waterborne infectious disease. Numerical simulation estimating the risk was developed depending on land use, diffusion of E.coli and flood water depth. We can understand high and low risk areas by the simulation results.

The infection risk of surface water use on middle flood magnitude in the lower Mekong
(Kazama et al., Sustainability Science, 7(1), pp.45-54, 2012.)

Ecology and Water

Habitat estimation
Hydrological conditions are highly related with water creature habitat. This means that hydrological model will evaluate habitat of aquatic organism. This concept was introduced by HSI on HEP. Here HSI is Habitat Suitability Index and HEP is Habitat Evaluation Procedure.

HSI distributions of Luciola lateralis (Japanese firefly, Heike Hotaru) in the Natori River Basin
(Nukazawa et al., Ecological Modelling, 222(20-22), pp.3718-3726, 2011.)


Genetic diversity
Integration of results for several species by above method can evaluate species diversity. On the other hand, we are observing genetic information of benthic insect in rivers. Comparing these, we will estimate genetic diversity in a basin under much discussion.

Benthic animals collection in Wasada River

Climate Change

Flood damage cost projection
When we consider the adaptation for climate change, an option in the adaptations should be discussed in view of the cost. A damage cost map in the future supports decision making for the adaptation in spatial and temporal.
million USD
Distribution of increase of potential damage cost from rainfall with 50- to 100-year return periods
(Kazama et al., Sustainability Science, 4(1), pp.61-69, 2009.)


Landslide projection
Heavy downpour affects not only flooding but also landslide. Japan is covered with steep mountains and landslide is the frequent water disaster. A future projection map can discuss the countermeasure for slope failure with landuse and population data.

Developed landslide hazard probability maps for extreme precipitation in 30 years return period
(Kawagoe et al., Hydrology and Earth System Sciences, 14, pp.1047-1061, 2010.)